Flexible Multi‐Material Fibers for Distributed Pressure and Temperature Sensing

Abstract

With the recent development of wearable electronics and smart textiles, flexible sensor technology is gaining increasing attention. Compared to flexible film‐based sensors, multimaterial fiber‐based technology offers unique advantages due to the breathability, durability, wear resistance, and stretchability in fabric structures. Despite the significant progress made in the fabrication and application of fiber‐based sensors, none of the existing fiber technologies allow for fully distributed pressure or temperature sensing. Herein, the design and fabrication of thermally drawn multi‐material fibers that offer distributed temperature and pressure measurement capability is reported. Thermoplastic materials, thermoplastic elastomers, and metal electrodes are successfully co‐drawn in one fiber. The embedded electrodes inside the fibers form a parallel wire transmission line, and the local characteristic impedance is designed to change with the temperature or pressure. The electrical frequency domain reflectometry is used to interrogate the impedance change along the fiber and provides information with high spatial resolution. The two types of fibers reported in this manuscript have a pressure sensitivity of 4 kPa and a temperature sensitivity of 2 °C, respectively. This work can pave the road for development of functional fibers and textiles for pressure and temperature mapping.

Textile Technology for Soft Robotic and Autonomous Garments

“…Yu and colleagues used thermal‐drawing‐based coextrusion to form a composite monofilament yarn from two copper conductors separated by a deformable SEBS layer, all of which were contained by a polycarbonate shell to strengthen the material stack for the drawing process. [ 409 ] A high frequency signal is sent through these conductors and, when they are pressed, a difference in impedance resulting from a change in the distance between the two conductors can be measured. This impedance change reflects some of the incident pulse of the signal, and information from the reflection can be used to calculate a time domain which can help to reconstruct the position and magnitude of the pressure for two simultaneous locations.…”

3D Printing in Fiber-Device Technology

“…A variety of intracortical probes have been developed using fiber drawing technology, including electrodes, fluid injection channels, and optical waveguides, for electrophysiology and optogenetics applications which were tested in wild-type mice [96]. Pressure and temperature distributed measurements are possible along a fiber using copper electrodes on either side of a core material that responses to pressure or temperature changes [97]. Ultrasound sensing was enabled in fibers using piezoelectric materials to be weaved into fabrics [60].…”

Chip on a fiber toward the e-textile computing platform

“…Fiber electronics are of considerable interest for wearable applications and smart textiles, which can facilitate communication and the interaction between humans and their surroundings 1−3 . As a basic element of functional textiles, the one-dimensional (1D) form of the thread-like bers offers high exibility, isotropic deformations, breathability, and lightweight in fabric structure 4,5 . The 1D functional bers can be further processed into two-dimensional (2D) textiles and three-dimensional yarn con gurations through traditional textile engineering techniques, such as twisting, weaving, sewing, knitting, knotting, interlacing, etc 5,6 .…”